A prospective, interdisciplinary study will be continued concerning immunologic response of children and adults in whom postpericardiotomy syndrome develops. Objectives are to (1) identify pathogenesis of the syndrome, (2) learn whether there is a correlation between clinical manifestations and circulating antibodies against myocardium and certain viruses, (3) develop a specific diagnostic test, (4) determine optimal management and (5) if possible, prevent the complication. Our studies on a triple-blind basis in 400 children undergoing intrapericardial procedures indicated a correlation between the presence of syndrome, which occurred in 27% of subjects, and high titer of antiheart antibody (AHA) determined by immunofluourescent technique, and a fourfold or greater rise in complement-fixing antibody against one or more of eight viruses which were prevalent in the community. We propose to expand that study to include adults undergoing intrapericardial surgery or manifesting the syndrome after sustaining myocardial infarction or pericardial trauma to learn whether the same associations occur in adults as in children and in the other two clinically similar syndromes in different settings. Clinical management will be standardized. We shall evaluate at prescribed intervals clinical syndrome in the patient and concurrently measured serum antibody against myocardium and 8 specific viruses. Heart-reactive antibody will be determined by immunofluorescent techniques. Adsorption studies to help characterize the antibody will include study of virus-infected cell lines as well as in vitro virus absorption in serum with high AHA. Cellular studies will test binding of circulation lymphocytes from patients with PPS to determine specific cellular reactivity for heart tissue antigens and to test effect on beating heart cells. Purified cardiac tropomyosin will be used as a test antigen to develop a means of quantitating humoral immune response in PPS.